Why do you rename your source images? I’ve never renamed any RAW files.

I could probably go on for a while….

1. Every photo should be uniquely identified, and camera-generated names don’t guarantee that happens. For example, _DSC1234 would repeat each time the camera passes 9999.
2. Secondly, there’s nothing sacrosanct about the names added by the camera, so why not make it meaningful in a variety of contexts (eg Explorer or Finder) by adding the date and perhaps some text description?
3. Third, it’s handy to provide clients with sequentially-numbered photos, rather than the jumbled alphanumeric file names generated by some cameras.
4. Fourth, also giving clients sequentially-numbered photos means they don’t notice gaps and ask to see images which you may have deleted for whatever reason.
5. Fifth, a scheme such as YYMMDD_1234 also helps you check the completeness of what’s in a folder. If the files are numbered 1-257, you know that you should have at least 257 pictures and that there’s a problem if 125, 126, 127 are missing.